Subbing photographic film



P 6, 1958 e. F. NADEAU EI'AL 2,852,378

SUBBING PHOTOGRAPHIC FILM Filed Nov. 1, 1955 Fig \ GELAT/IV AND SILVER HAL lDE VGELAUA/ 44/0 CHROM/C CHLORIDE r CELLULOSE' ACETATE i Fig. 2

. eemmvmvo SILVER HAL/DE Mean/1v AND CHROM/C CHLORIDE v 7 81/772 ACRYLATE -ACRYL/C ACID-Vl/VYUDENE a/11.0mm- TERPOLYMER POLYETHYLEWE' ,TEREPHTHALATE Fig. 3

\\ .w GELAT/N AND SILVER HAL/0E 4/ -6LA77N AND CHROM/C CHLORIDE K cam/Loss TR/ACETATE A ORNEY SUBBING PHOTOGRAPHIC FILM Gale F. Nadeau and Walter R. White, Rochester, N. Y., assignors to Eastman Kodak Company, Rochester, N. Y., a corporation of New Jersey Application November 1', 1955, Serial No. 544,164

4 Claims. (Cl. 96-87) This invention relates to photographic film elements and is particularly concerned with transparent photographic film elements having an improved anchorln-g substratum (commonly known as a subbing layer) between the film base and the water-permeable colloid layer or layers disposed thereon.

It is common practice in the manufacture of photographic films to apply a thin layer of gelatin from a dispersion in a solvent onto the film base before the lightsensitive silver halide emulsion layer is applied. This subbing layer is usually necessary in order to achieve States Patent f adequate adhesion between the emulsion layer and the,

film base. Moreover, the degree of adhesion of the layers must be properly controlled in order to avoid the formation of a product which is brittle or in whichthe layers peel from the support. If the degree of adhesion is too great, the film may be brittle and the layers crack when the film is bent. If the adhesion is too slight, the layers are likely to peel or strip from the supportwhen the film is dry or when it is treated in the developmg or fixing baths or other processing solutions.

U. S. 2,271,228 issued to Nadeau et al. teaches that a subbing layer of gelatin can be applied to a somewhat hydrophilic surface such as partly hydrolyzed cellulose ester or a mixture of gelatin and cellulose nitrate. When photographic emulsions made from gelatin are'deposited thereon, good adhesion is obtained. Chromic chloride is used as a hardener in the subbing layer deposited on the hydrophilic surface in an amount of from 34% to about 2 /z% of the weight of gelatin contained in the sub.

are synthetic resins such as the terephthalate polyesters which are not subject to easy treatment to render them hydrophilic. Certain of these resins must be coated with special resinous subs such as vinylidene chloride containing copolymers which are then subbed. These vinylidene copolymers are themselves relatively hydrophobic.

In some instances, it is necessary to use solvent IIllX- tures in order to obtain adhesion of a subbing layer, but v the solvents which are strong enough to attack the synthetic .resins are in some instances detrimental to the photographic properties of emulsions subsequently used and may also tend to afiect the transparency of the film base. Moreover, coating difiiculties involved in subbing with mixtures containing volatile solvents require removal systems, explosion safeguards, health protection devices and the like.

We have found surprisingly enough that certain subbing mixtures may be applied to cellulose ester film base without the step of coating the base with a hydrolyzed cellulose ester coating in order to render the base hydrophilic. In addition We have found that we can sub terpolymer coatings without rendering them first hydrophilic. Moreover, our subs may be deposited from an Many of the materials which have utility as film base described in Example III, following.

chloride followed by a photographic light-sensitive gelatin 2,852,378 Patented Sept. 16, 1958 all, aqueous solvent or from one containing water and "an organic solvent.

One object of this invention is to provide new and improved photographic film elements, and particularly photographic film elements having improved anchoring or subbing layers. A f urther object of this invention is to provide anchoring or subbing materials which have excellent adhesion to-hydrophobic film base materials whether applied in an all aqueous medium or in; an aqueous solvent mediuml. Another object is to provide a hardener. in a subbing layer which is compatiblewith photographic emulsions which permits controlling. wet stripping or frilling of photographic film.

We have discovered that we can apply a gelatin layer onto a relatively highly hydrophobic surface by incorporating an amountof chromic chloride from 12 to 20.0% of the weight of gelatin in the sub. These subbinglayers may be applied to cellulose ester film base such as .cellulose acetate, cellulose triacetate, cellulose acetate butyrate and the like Without the necessity of hydrolyzing the film base. They may also be applied over such hydrophobic surfaces as copolymer layers used to coat certain polyester film bases such as terephthalate polyesters. A typical such layer, containing vinylidene chloride, is Other polymeric compositions include those polymerized from monomeric mixtures containing butyl acrylate, styrene and acrylic acid; butyl acrylate, acrylonitrile, acrylic acid; vinylidene chloride, acrylonitrile and .itaconic acid; vinylidene chloride, itaconic acid and an acrylicacid ester; and the like.

In the accompanying drawings, Figs. 1 to 3 aresectional views of photographic film subbed according to our invention. p 4

Fig. 1 shows a cellulose acetate film base coated With a layer" ofgelatin subbing containing-chromic chloride. Over the gelatin layer, is coated a photographic silver halide emulsion; w 1

Fig.2 shows a polyethylene terephthalate film base having coated thereon a layer comprising a copolymer of butylacrylate, acrylic acid and vinylidene chloride. On

this surface is coated, a gelatin sub containing chromic emulsion.

Fig. 3 shows a cellulose triacetate film base on which has been coated a gelatin subbing containing chromic chloride followed by coating with a light-sensitive gelatin emulsion.

As -used herein,- cellulose acetate is intended to mean cellulose acetate having an acetyl content of less than 42%. Cellulose'triacetate is intended to mean cellulose acetate having an acetyl content of atleast 42%. The subbing compositions embodying our invention can be coated on the hydrophobic film base by any suitable technique from either an all aqueous solution or from anaqueous mixture containing'an organic solvent.

- -It can'be' deposited byany of the conventional methods i such as by immersing-the film base into a solution-of the provided with 'a' doctor blade methods.-

coating'material, by spraying, by coating from a hopper or by similar Well known The" thickness of the layer can vary over a wide range such as from 0.01 mil. to 0.1 mil. or greater. Generally, anchoring layers from .01 mil. to .05 mil. are most satisfactory.

The following examples illustrate our invention, it being understood that the examples are included for the purposes of illustration and not to limit the scope of the invention unless otherwise specifically indicated.

Example 1 A solution containing 0.75% gelatin, 1.0% acetic acid, 0.3% cellulose nitrate, 0.0225% (3% the weight of gelatin) chromic chloride, 1.5% water, 60.0% acetone Example 2 A solution containing "'10:8%" gelatin," 1.6% 'water, 1 :024% chromic chloride (3%:th'e weight ofgelatin),

1 1.0% lactic acid-,'60%:methylene chloride, and the balance methyl alcohol was"roller coatedonto plasticizedcellulose-acetate sheeting 'over'whichyvasthen coated atlightsensitive gelatin emulsion. The adhesion was poor be- --fore,-:during ,andafterprocessing; and .inisome' instances floated off the cellulose acetate support-during processing.

When the chromic chlorideconcentration*Was'doubied to "-".048%(6% the weight of gelatin); the adhesion was enhanced only slightly-Whenthe-concentration of '"chromic chloride was'increased toi096% "(12%" the weight of gelatin); the anchorage ofthelight-sensitive -'--gelatinemulsion 'to; the support was excellentfbefore, during and after processing.

.Example 3 -A*copolymer of 30%-butyl acrylate;%4% acrylicacid' and 66% vinylidene chloride was prepared as an 'aqueous dispersion and "applied to polyethylene terephthalate *--*sheeting byroller coating sothat it adheres =tenaciously.

This surface was then "coated with a' solution of 0:5% I

gelatin, 0.25% ;Saponin, 0.6%? acetic acid; 0.015%

'chromic chloride "(3%'the-weight of'gelatin-)-and the balance water. A light-sensitive gelatin-emulsionfcoated thereon had only fair adhesion before and' 'afterprocessing and verypooradhesion duringprocessing: Increasing M the concentration ofchromic chloride to' 0.125 (25% the weight of gelatin) and 0.25 %"(50%"- the-weight of gelatin) progressively improved adhesion-*before,-*during and-"after processing,--"but-when the -concentration of -'chromic-chloride-was'--increased 0 0.5% (-100%-the weight of gelatin), the adhesion' of"the""light sensitive gelatin emulsion was brought to aneXcellenbedemarided H by'normal use.

Example 4 A solution containing 0.75%, gelatin, l.0% acetic acid,

60% acetone,.1 /2% water,.andtherbalancemethyl alco- 50 hot was roller coated onto a plasticized cellulose: acetate surface; Adhesion of the lightwsensitiye. gelatinemulsion wcoated. onto the dried'subbing was good.- @Adding chromic 1s chloride. up to 0.375% the,.-w.eight of gelatin) resulted in adhesion otthe overcoated light-.sensitive -emula-sion becomingprogressively: :worse it both before during ;and after processing, indicating; that.-.-with-: this-subbing -.--mixture, a small amount of-chromic zchloride was :not

-.-beneficial.

Y fiThe nature of the light-sensitive silver-halide emulsion 60 is=not critical and theilight-sensitive. layer may: consist oil-simple or mixed silver.hali'des-..dispersed imvanous ;:,-.types of water-permeablev binding. agents..- Thus, .-the emulsion coatings may-contain -silver-.chlor de,.- silver 4 bromide, silver chlorobromide or silver iodobromide in ""gelatin or equivalent water-penneable, natural or synthetic colloids. Although aqueous sub dispersions provide entirely satisfactory adherence, aqueous solutions 5 containing volatile solvents may also be used. If a volatile solvent is desired, one which has a solubilizing efiect on the film so as tot-increase the adhesion, may be used. .Suitable solvents include acetone, methyl ethyl ketone, methylene chloride and the like. Other layers O:may.-.also be incorporated in conjunction -with these -.anchoring layers-such as-water-sensitive celluloseesters, waterproofing layers,- antihalation layers, filtering layers and the like.

The use of subbing layers containing an increased amount of chromic chloride avoids the necessity of coating cellulose ester film base with a hydrolyzed cellulose ester layer in order to make the base hydrophilic. It also avoids the necessity of coating the cellulose ester base with other hydrophiliecoatings'such as'gelatin and cellulose nitrate or the like. Since one of-theseqsteps is not required, an. economic saving results.

We claim:

1. A'photographic element comprising a polyethylene terephthalate film base, a first subbing" comprising a .vinylidene chloride butyl acrylate-acrylic acid'terpolymer, .asecond subbing layer comprising gelatin and from 12 to 11200% chromic chloride based onthe weight of the-gelatin inthesubbing layer and a light-sensitive gelatino silver .halide emulsion. V

v2. A photographic element comprising apolyethylene ,trephthala'te film base,- a first subbing comprising a'vinyl- .iden'e. chloride terpolymer, a second subbing layer-comprisinggelatin'and: from 12 to 200% chromic chloride .based on the weight of the gelatin in the subbing layer .and'a. light-sensitive gelatino-silver'halide emulsion.

'3. A photographic element comprising a polyethylene terephthalate ,film base, a first subbing comprising a butylacrylate, styrene'and acrylic acidterpolymer, a second subbinglayer comprising gelatin and from 12 to 40: 200%*chromic chloride based onthe weight of the gelatin in the subbing layer and a light-sensitive gelatino silver halide emulsion.

4. A photographic element'comprisinga polyethylene te'rephthalate '"film base, a first subbing comprising an "arcylonitrile acrylic' acid and butyl'acrylateterpolymer, a second subbing layer'comprising gelatin and from 12 to 200% chromicchloridebasedon the weight of: the

""gelatin in the subbing layer and a light-sensitive gelatino silver halide emulsion.

if References Citeddn the file -of ..this patent UNITED STATES PATENTS 2,271,228 Nadeau et a1. Jan. 27;1'942 2 ,698,235 Swindells Dec: 2851954 2,703,284 White et al. Mal. 191955 2,776;2l9 "Hoyt et a1. =Jar1. 1,31957 OTHER REFERENCES Journal of Society ChemicalIndustries, 7B,- 1903, '-5.vol..22, page 1358. Gelatin ,Rendered Insoluble by Salts of Chromium S esquioxideyComposition of-... A. L. Lumiere and A. Seyewetz. 

1. A PHOTOGRAPHIC ELEMENT COMPRISING A POLYETHYLENE TEREPHTHALATE FILM BASE, A FIRST SUBBING COMPRISING A VINYLIDENE CHLORIDE BUTYL ACRYLATE-ACRYLIC ACID TERPOLYMER, A SECOND SUBBING LAYER COMPRISING GELATIN AND FROM 12 TO 200% CHROMIC CHLORIDE BASED ON THE WEIGHT OF THE GELATIN IN THE SUBBING LAYER AND A LIGHT-SENSITIVE GELATINO SILVER HALIDE EMULSION. 